Optimize services for large datasets

**Feature request**
It would be great to have caching for controllers.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_caching` with default `false`.

The issue mentions controllers, services, and a new enable_caching configuration option, but names no files, tests, or entry points. First locate the controller and configuration code, then clarify the caching scope, invalidation behavior, and acceptance tests; done should include a disabled-by-default option and verified caching behavior.

Written by the indexing model from the issue text.